The Maximum Achievable Control Technology (MACT) Standards for hazardous waste incinerators will impose strict regulatory limits on the emission of chlorinated dioxins and furans, other toxic organic compounds, toxic metals, hydrochloric acid, chlorine gas, and particulate matter. These emission standards will affect the future operation of several U.S. Department of Energy (DOE) incinerators, which may have problems meeting the dioxin and mercury emission limits. Mercury exists in many of the hazardous and mixed wastestreams being thermally treated throughout the DOE complex. Mercury contained in the wastestreams is vaporized in the incineration process and is transferred almost entirely to the offgas. To meet the MACT Standard for mercury, DOE incinerators will need to integrate mercury removal technologies into their offgas systems or limit the processing of mercury-bearing wastestreams. To address the mercury emission problems of the DOE Incinerators, MSE Technology Applications, Inc. (MSE), in conjunction with the DOE-Mixed Waste Focus Area (MWFA), has evaluated and is presently testing three technologies designed to reduce mercury emissions. A paper presented at the 1999 Incineration and Thermal Treatment Technologies Conference, in Orlando, Florida, provided an overview of the technologies and preliminary test results. One of the technologies currently being tested is carbon injection. Test objectives consist of determining the optimum carbon injection rate to meet the MACT Standards, determining the system removal efficiency at various carbon injection rates, and determining the mercury-loading of the carbon. Because DOE hazardous waste incinerators treat large quantities of chlorinated wastes, the carbon injection test campaign focused on treating offgas containing both elemental mercury and mercuric chloride. Results of these tests and the recommendations based on these results are the subject of this paper.
展开▼
